Complexes trigonal bipyramidal

Bismuth ligands, 2,989-1061 bonding, 2,1030-1041 7i bonding, 2, 1033-1039 trigonal bipyramidal complexes, 2,1036 Bismuth line, 3,294 Bismuthotungstates, 3, 1042 Bismuth pentafluoride, 3, 292 Bismuth tribromide, 3, 291 Bismuth trichloride, 3, 290 Bismuth trifiuoride, 3, 290 Bismuth triiodide, 3,292 Bismuth trioxide, 3,284 2,2 -Bisphenol metal complexes color photography, 6,109 Bis(trimethylene)triamine metal complexes, 2, 49 4,4 -Bi-l, 2,4-triazolyl metal complexes, 2, 89 polymers... 

Trigonal bipyramidal complexes in which a metal ion is surrounded by five ligands are more rare than octahedral or tetrahedral complexes, but many are known. Will trigonal bipyramidal compounds of the formula MXfY2 exhibit isomerism If so what types of isomerism are possible ... 

Thiourea Ugands can be bounded to the metal centre through one nitrogen atom, the sulfur atom, or the C = S double bond. These coordination modes were studied by density functional theory calculations for Rh-thiourea complexes (Scheme 13). No stable structure was attained by optimisation of the nitrogen coordination mode I but optimised geometries as trigonal-bipyramidal complexes were obtained for modes II and III. An coordination is determined for the latter complex through both S and C atoms. As this... 

Mechanism a) operates if the tin-halogen bond of this trigonal bipyramidal complex is broken. 

Mechanism b) applies if a second solvent molecule is added at the tin atom of this pentacoordinate complex. The influence of the halogen atom can safely be predicated if mechanism a) is operative. The equilibrium constant for the formation of the trigonal bipyramidal complex is not very different for X=C1 and for X=Br31). Furthermore, since Cl( ) is harder than Br( the cleavage of the tin-... 

Dioxygen and its ions can bind in mononuclear and dinuclear structures in a number of ways,962 as illustrated in Scheme 1. The typical reaction of dioxygen with Co compounds involves a number of these binding forms, outlined in Scheme 2. Mononuclear Co111—peroxo complexes are relatively rare, but yellow trigonal bipyramidal complexes [Co(02)L2]+ (L = chelating phosphines dppe or dppp) have been characterized structurally where the 022 is bonded to the Co in the side-on r]2 form (Co—O 1.858(7) 1.881(4) A), with O—O stretching frequencies ( 870 cm-1) consistent with Coin-peroxo speciation.963... 

A further reaction of [Ir(cod)Cl]2 with 3,4-dimethylphosphaferrocene, (355), yields the trigonal-bipyramidal complex [Ir(355)3(cod)]BF4, (356). 79 (356) reacts with H2 under pressure to give [Ir(355)4H2]+. Reaction of Ir(cod)Cl]2 with o-diphenylphosphinobenzoic acid ethyl ester (dpes), (357), yields [IrCl(cod)(dpes)], where dpes is acting as a monodentate P-donor-atom ligand.580 When dpes is reacted with [Ir(cod)2]BF4, then the structurally determined... 

In the bifunctional radiopharmaceuticals, Tc and Re complexes that are suitable for coupling to antibodies are almost square-pyramidal oxo complexes of tetradentate ligands, as mentioned earlier. Spies et al. [65] recently studied the syntheses and structures of rhenium complexes with a tetradentate NS3 tripod ligand 2, 2,, 2"-nitrilotris(ethanethiol) (l in Fig. 9) as an interesting alternative to the oxo complex. Such ligands could lead to weakly polar, trigonal-bipyramidal complexes in which the metal atom is more strongly shielded than in the square-pyramidal oxo complexes. Schemes for the syntheses... 

Sketch all of the geometrical isomers possible for trigonal bipyramid complexes having the formulas (where AA is a bidentate ligand) (a) MX4Y (b) MX3Y2 (c) MX3(AA). ... 

Although Co(II) forms both square pyramidal and trigonal bipyramidal complexes, most spectroscopic studies have been performed on the latter variety. Norgett and Vernnzi (76) analysed the d—d spectrum of [CoCl(QP)]+ where QP is fra-(o-di-phenylphosphinophenyl) phosphine. This has a CoP4Cl chromophore, with distorted Cjy symmetry. The ground state is a spin doublet, and three spin-allowed d—d transitions were observed. Only two AOM parameters were defined, eCT(eq) and eCT(ax). 

The spectra of the trigonal bipyramidal complexes [FeX(Me6tren)]X have been reported in detail (8). X-ray analysis (31) has shown the complex [FeBr(Me6tren)]Br to have a Csv structure with 8 = 81 ° (Fig. 10). The spectrum of this compound shown in Fig. 12 exhibits bands of low intensity above 14 kK which must be attributed to spin-forbidden transi-... 

It should be noted that these spectra bear the expected similarity to those of trigonal bipyramidal complexes of the d configuration, for example TiBr3(NMe3)2. 

Large numbers of five-coordinate copper(II) complexes in several stereochemistries are known. The spectra which have been most studied with a view to interpretation are those of the trigonal bipyramidal complexes, for which assignments have been proposed on the basis of molecular orbital, angular overlap, and crystal-field models. 

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